JPH0145278Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an excitation device for an emergency power supply, and is particularly suitable for supplying power to large-capacity load distribution equipment by adopting the most effective power supply method. The present invention aims to provide an excitation device that can reduce capacity.

In general, when planning an emergency power supply system such as an engine generator for load equipment such as a large building or even a large manufacturing facility, the emergency power supply equipment will be larger than the receiving capacity of the load equipment. It is well known that equipment is installed with the capacity limited to approximately 1/2 to 1/5 times. Therefore, when looking at the power distribution equipment as a load, it is actually necessary to supply power that is twice to five times as large as that of the emergency power supply device. To illustrate this point with a specific example, when a power transformer that serves as a receiving power source for load equipment is charged by an emergency power supply device, as is well known, a large-power magnetizing inrush current flows. This magnetizing inrush current can reach several times the full load current in some cases, and the emergency power supply must have enough overcurrent capability to withstand such a high power magnetizing inrush current. . In the past, events such as magnetizing inrush current are well known, but the emergency power supply itself is designed to deal with unforeseen situations such as commercial power outages, and moreover, in the event of an abnormality, it is necessary to respond immediately. In line with the original purpose of supplying high-quality power to load equipment, conventionally, the capacity of the emergency power supply device itself has been large enough to take into account the excitation inrush current of the transformer. This is the actual situation. It is very uneconomical to use a large-capacity emergency power supply to deal with such unexpected situations, and there is an urgent need for countermeasures in this regard.

The present invention has been devised in view of this point, and in particular, when supplying power to power distribution equipment, the generator output voltage is increased from the normal state only during the transition period within a range that does not interfere with the operation of the power distribution equipment itself. The main feature is that large-capacity power distribution equipment is charged in a reduced voltage state, and will be described in detail below based on examples.

Figure 1 shows a specific configuration example according to the principle of the present application, in which 1 is the armature of the generator, 2 is its field winding, and 3 is the main engine's field winding 2 that is excited. In the armature of an AC exciter, 4 indicates its field winding. 5
is a permanent magnet generator that serves as a predetermined excitation source in case of a short circuit accident on the load side, and the voltage signal output from this permanent magnet generator is used as a control input quantity for control in this application. However, it is not limited to permanent magnet generators, for example, batteries used as control power sources, small generators for speed detection, etc. may be used, and these permanent magnet generators, batteries, and A small generator for speed detection, etc. shall be referred to as a pseudo control voltage generation circuit in this application. 6 is a rotary rectifier for rectifying the armature output of the AC exciter to excite the field winding 2; this rotary rectifier is, as is well known, formed by connecting thyristors in a pure bridge; A type in which only diodes are bridge-connected, and a type in which a thyristor and a diode are connected in a mixed bridge are applied, and the field winding 2 and the armature 3 of the AC exciter are arranged on the same axis in a rotating part. . Note that FIG. 1 shows a case where diodes are bridge-connected as a rotary rectifier. 7 is an automatic voltage regulator that controls the generator output voltage by adjusting the excitation current that excites the field winding 4 of the AC exciter, and 8 is a voltage setting device for setting the required voltage. , 9 is a voltage detection transformer for extracting a voltage component related to the terminal voltage from the generator output bus;
is an AC circuit breaker for turning on power distribution equipment. As is clear from the above principle configuration diagram, the present application uses the voltage setting device 8 as the control input amount of the automatic voltage regulator.
The voltage command amount given by the above, the voltage detection signal derived from the pseudo control voltage generation circuit 5, and the voltage detection signal derived from the detection transformer 9 are three quantities, and with the various quantities of these three signals, , attempts to control the output of the generator by adjusting the excitation of the AC exciter when charging a predetermined load. A specific circuit diagram of such a generator output voltage control method is shown in FIG. 2, in which the same parts as in FIG. 1 are given the same symbols, and 11 is a voltage detection transformer. This is a rectifier circuit that rectifies the terminal voltage component led from the voltage detector 9. Although only one diode is shown in the figure, as is well known, the first voltage detection circuit itself can be constructed by bridge-connecting diodes. configured. 12 ₁ -12 ₂ are detection resistors for extracting a required voltage detection signal, and constitute a voltage synthesis circuit. Reference numeral 13 denotes a rectifier circuit that once rectifies the required power output from the pseudo voltage generation circuit 5, typically a permanent magnet generator, and constitutes a second voltage detection circuit. 14-15 are current limiting resistors, 16 is a capacitor, and ₁₀₁ is a normally open contact of a relay (not shown) which operates on the condition that the circuit breaker shown in FIG. 1 is closed. A charging/discharging circuit is constructed in which a charging operation is performed by the current limiting resistor 14 and the capacitor 16, and a discharging operation is performed by the capacitor 16, the current limiting resistor 15, and the normally open relay contact ₁₀₁ .

Now, the operation of this embodiment configured as described above will be explained in detail with reference to Figs. is detected by an undervoltage detection relay, etc., and emergency power equipment such as an inverter (not shown) operates without momentary interruption based on this detection signal, securing power only for the pre-specified load, and at the same time The emergency power supply shown in FIG. 1 starts to start. However, on the emergency power supply side in Fig. 1, certain operations are performed to prevent overexcitation of the generator that occurs when the engine is idling, for example, it is de-energized up to approximately 20% to 30% of the rated output frequency. Thereafter, predetermined control is performed to gradually increase the excitation and the output voltage to complete the startup. In this starting-to-steady-state control process, in the present invention, first, the _first
Let the voltage detection signal value of
3 → Resistor 14 → Detection Resistor 12 Let _VH be the second voltage detection signal value led through the path ₂ , then the detection voltage obtained by combining these voltage detection signal values and the voltage setting signal from the voltage setting device 8. are compared, and the excitation current supplied to the field winding 4 of the AC exciter is adjusted using the deviation amount through the automatic voltage regulator 7. Upon starting, adjust the neutral point of the detection resistor 12 ₁ and set the first voltage detection signal V _D to the setting device 8.
equal to the reference voltage value V ₀ . When starting, the second voltage detection signal value V _H derived from the pseudo control voltage generation circuit 5 via the charging/discharging circuit is the charging time constant.
A predetermined control is performed so that the generator output voltage increases according to C16-R14 and decreases by an amount corresponding to this second voltage detection signal value _VH . Therefore, at the completion of a predetermined start, the voltage output from the emergency power supply device shown in FIG. 1 is lower than the rated voltage by an amount corresponding to the output voltage of the pseudo control voltage generation circuit 5. , furthermore, during such start-up, the second
The illustrated capacitor 16 is charged to a predetermined value through a path from the rectifier circuit 13 to the resistor 14 with the illustrated polarity. In this state, when it is detected that the emergency power supply shown in Figure 1 has completed its start, the uninterruptible power supply, such as an inverter, which has been in operation until the emergency power supply completes the specified start, is activated as the main power supply. The circuit is opened, and at the same time, the AC circuit breaker 10 shown in FIG. 1 is turned on, and the necessary power supply from the emergency power supply device shown in FIG. 1 to the load equipment (not shown) is started. At the start of such power supply, in the present application, as described above, the generator output voltage is a value that is sufficiently reduced compared to the rated voltage, and when it is detected that the AC breaker 10 is closed, the voltage as shown in the figure is set. At the same time as the normally open contact 10 ₁ of the detection relay is closed, a switch (not shown) on the input side of the rectifier circuit 13 is opened, and the charge charged in the capacitor 16 is transferred from the capacitor 16 to the resistor 15 to the normally open contact 10 ₁ is descharged through the path of Therefore, as is clear from FIG. 2, the charging voltage of the capacitor 16 is
As C ₁₆ −R ₁₅ is discharged with a discharge time constant, the voltage V _H between the terminals of the detection resistor 12 ₂ gradually decreases, and a detection signal is obtained by combining the detection voltages V _D and V _H. The amount, that is, the detected input amount of the automatic voltage regulator 7 becomes relatively smaller. What this means is that a relative decrease in the amount of detected input means that the reference value itself will equivalently increase; A predetermined excitation adjustment is performed based on the reference value, and the generator output voltage is gradually increased to the rated voltage. Note that when the capacitor 16 finishes discharging and the voltage across the terminals of the detection resistor ₁₂₂ becomes zero,
By adjusting the neutral point of the detection resistor 12 ₁ , the output of the first voltage detection circuit is set to the first voltage detection signal value V _D ,
Needless to say, a predetermined control in a steady state is thereafter performed based on this first voltage detection signal value V _D and the reference voltage value from the setter 8. Therefore, according to the present application, when charging large-capacity load equipment, such as a power transformer, the output voltage of the emergency power supply device is set in advance to a standby state that generates an output voltage sufficiently lower than the rated voltage. In this state, the transformer is charged and the output voltage is gradually boosted under a predetermined control, so even if an excitation inrush current flows, it is faster than conventional devices that apply full load voltage. It is clear that the capacity of the emergency power supply device itself can be reduced by sufficiently suppressing the value.
In the above explanation, an example was given in which an uninterruptible power supply such as an inverter is operated to secure the required power until the emergency power supply completes startup, but depending on the condition of the load equipment, for example, Therefore, there are cases where only an emergency power supply such as an engine generator is installed without installing the above-mentioned uninterruptible power supply.
Even in the case of such load equipment, if the emergency power supply device is kept on standby at half voltage (referring to 1/2 of the rated output voltage) for a predetermined period of time using the method described above, and the load equipment is charged in this state, the above will be achieved. It is clear that this is effective, and Fig. 1 shows the case where the generator output voltage is indirectly controlled by adjusting the excitation current supplied to the field winding of the AC exciter. For example, there is a type in which the rotary rectifier is configured as both arms or one arm, and the field of the AC exciter is constant excitation, and the generator output voltage is controlled by controlling the thyristor of the rotary rectifier. It is obvious that the present application can be applied, and it is also obvious that the present application can be applied to a generator having brushes.

As described above, in the present invention, rather than charging large capacity load equipment at the rated voltage (full load voltage), it is charged at a sufficiently low voltage compared to the rated voltage, and the output voltage is gradually increased. Because of this, various effects can be achieved as shown below.

Even if the load equipment is a large-capacity power transformer, the capacity of the emergency power supply device can be significantly reduced because the excitation inrush current is controlled to be kept within a small predetermined range. I can do it.

Based on the above items, a very economical power supply device can be provided.

Since this method uses a method of gradually increasing the voltage setting command amount equivalently, the circuit configuration can be relatively simplified compared to the case where a function generation circuit is applied. can provide highly reliable equipment.

[Brief explanation of drawings]

Figure 1 shows the basic configuration diagram of the present invention, and Figure 2 shows the basic configuration diagram of the invention.
The figure is a circuit diagram showing a specific circuit configuration of the voltage regulator, which is the main part. 1 is the armature of the alternator, 2 is its field winding,
3-4 is an armature of an AC exciter and its field winding; 5 is a pseudo control voltage generating circuit; 6 is a rotary rectifier; 7 is an automatic voltage regulator.

Claims (1)

[Claims for Utility Model Registration] A first voltage detection circuit that guides the detection signal of the generator output voltage, a second voltage detection circuit that guides the output voltage of the pseudo control voltage generation circuit, and a predetermined voltage detection circuit before load application. a charging/discharging circuit that is charged with a voltage signal output from the second voltage detection circuit at a certain time, and that opens the second voltage detection circuit and discharges the charged charge after a load is applied; a voltage synthesis circuit that synthesizes a first voltage detection signal guided from the detection circuit and a second voltage detection signal guided from the second voltage detection circuit via the charging/discharging circuit; A voltage setting device that sets a reference voltage for generating a voltage, compares the composite detection voltage that is the output of the voltage synthesis circuit with the reference voltage, adjusts the excitation current of the AC exciter based on the deviation, and adjusts the generator output voltage. and an automatic voltage regulator that controls the voltage, and in the start-to-steady state control process, the first voltage detection signal of the composite detection voltage is set to the same value as the reference voltage, and before load application, the charging and discharging The generator output voltage is boosted to a predetermined value lower than the rated voltage based on the charging voltage of the circuit, and after load application, the generator output voltage is boosted to the predetermined rated voltage based on the discharge voltage of the charging/discharging circuit. Excitation device for emergency power supply.